// Copyright 2016 PingCAP, Inc.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// See the License for the specific language governing permissions and
// limitations under the License.

package tikv

import (
	"fmt"
	"time"

	. "github.com/pingcap/check"
	"github.com/pingcap/tidb/kv"
	log "github.com/sirupsen/logrus"
	"golang.org/x/net/context"
)

type testSnapshotSuite struct {
	OneByOneSuite
	store   *tikvStore
	prefix  string
	rowNums []int
}

var _ = Suite(&testSnapshotSuite{})

func (s *testSnapshotSuite) SetUpSuite(c *C) {
	s.OneByOneSuite.SetUpSuite(c)
	s.store = NewTestStore(c).(*tikvStore)
	s.prefix = fmt.Sprintf("snapshot_%d", time.Now().Unix())
	s.rowNums = append(s.rowNums, 1, 100, 191)
}

func (s *testSnapshotSuite) TearDownSuite(c *C) {
	txn := s.beginTxn(c)
	scanner, err := txn.Iter(encodeKey(s.prefix, ""), nil)
	c.Assert(err, IsNil)
	c.Assert(scanner, NotNil)
	for scanner.Valid() {
		k := scanner.Key()
		err = txn.Delete(k)
		c.Assert(err, IsNil)
		scanner.Next()
	}
	err = txn.Commit(context.Background())
	c.Assert(err, IsNil)
	err = s.store.Close()
	c.Assert(err, IsNil)
	s.OneByOneSuite.TearDownSuite(c)
}

func (s *testSnapshotSuite) beginTxn(c *C) *tikvTxn {
	txn, err := s.store.Begin()
	c.Assert(err, IsNil)
	return txn.(*tikvTxn)
}

func (s *testSnapshotSuite) checkAll(keys []kv.Key, c *C) {
	txn := s.beginTxn(c)
	snapshot := newTiKVSnapshot(s.store, kv.Version{Ver: txn.StartTS()})
	m, err := snapshot.BatchGet(keys)
	c.Assert(err, IsNil)

	scan, err := txn.Iter(encodeKey(s.prefix, ""), nil)
	c.Assert(err, IsNil)
	cnt := 0
	for scan.Valid() {
		cnt++
		k := scan.Key()
		v := scan.Value()
		v2, ok := m[string(k)]
		c.Assert(ok, IsTrue, Commentf("key: %q", k))
		c.Assert(v, BytesEquals, v2)
		scan.Next()
	}
	err = txn.Commit(context.Background())
	c.Assert(err, IsNil)
	c.Assert(m, HasLen, cnt)
}

func (s *testSnapshotSuite) deleteKeys(keys []kv.Key, c *C) {
	txn := s.beginTxn(c)
	for _, k := range keys {
		err := txn.Delete(k)
		c.Assert(err, IsNil)
	}
	err := txn.Commit(context.Background())
	c.Assert(err, IsNil)
}

func (s *testSnapshotSuite) TestBatchGet(c *C) {
	for _, rowNum := range s.rowNums {
		log.Debugf("Test BatchGet with length[%d]", rowNum)
		txn := s.beginTxn(c)
		for i := 0; i < rowNum; i++ {
			k := encodeKey(s.prefix, s08d("key", i))
			err := txn.Set(k, valueBytes(i))
			c.Assert(err, IsNil)
		}
		err := txn.Commit(context.Background())
		c.Assert(err, IsNil)

		keys := makeKeys(rowNum, s.prefix)
		s.checkAll(keys, c)
		s.deleteKeys(keys, c)
	}
}

func (s *testSnapshotSuite) TestBatchGetNotExist(c *C) {
	for _, rowNum := range s.rowNums {
		log.Debugf("Test BatchGetNotExist with length[%d]", rowNum)
		txn := s.beginTxn(c)
		for i := 0; i < rowNum; i++ {
			k := encodeKey(s.prefix, s08d("key", i))
			err := txn.Set(k, valueBytes(i))
			c.Assert(err, IsNil)
		}
		err := txn.Commit(context.Background())
		c.Assert(err, IsNil)

		keys := makeKeys(rowNum, s.prefix)
		keys = append(keys, kv.Key("noSuchKey"))
		s.checkAll(keys, c)
		s.deleteKeys(keys, c)
	}
}

func makeKeys(rowNum int, prefix string) []kv.Key {
	keys := make([]kv.Key, 0, rowNum)
	for i := 0; i < rowNum; i++ {
		k := encodeKey(prefix, s08d("key", i))
		keys = append(keys, k)
	}
	return keys
}
